DESKTOP x1k1A                                ͻ
                                       STE       
                                 bit assignments 
                                ͼ
                   Ŀ
                    Video Base [b23-b0]=video base
                   
              Ŀ
               Horizontal Jump   b3-b0=horizontal jump in bits
              
                Ŀ
                 Vertical Jump   b7-b0=vertical jump in words
                
               Ŀ
                Color Register  b11-b8=[b0/b3-b1]=red   level
                                 b7-b4=[b0/b3-b1]=green level
                                 b3-b0=[b0/b3-b1]=blue  level
               
                        Ŀ
                         Fires      b3=fire 3 (0:yes  1:no)
                                    b2=fire 2 (0:yes  1:no)
                                    b1=fire 1 (0:yes  1:no)
                                    b0=fire 0 (0:yes  1:no)
                        
                       Ŀ
                        Sticks b15-b12=stick 3 (up down left right 0:yes 1:no)
                                b11-b8=stick 1 (up down left right 0:yes 1:no)
                                 b7-b4=stick 2 (up down left right 0:yes 1:no)
                                 b3-b0=stick 0 (up down left right 0:yes 1:no)
                       
      Ŀ
       X Paddle 0  Y Paddle 0   b7-b0=x|y paddle 0
      
      Ŀ
       X Paddle 1  Y Paddle 1   b7-b0=x|y paddle 1
      
                        Ŀ
                         X Pen   b9-b0=x pen (1 unit=4~=500 ns)
                        
                        Ŀ
                         Y Pen   b9-b0=y pen
                        
             Ŀ
              Control Register   b1-b0=mode
                                       00:stop
                                       01:play
                                       11:continual play
             
                    Ŀ
                     FREQuency      b7=stereo
                                       0:yes
                                       1:no
                                 b1-b0=frequency
                                       00: 6258 Hz
                                       01:12517 Hz
                                       10:25033 Hz
                                       11:50066 Hz
                    
                   Ŀ
                    Sound Base [b23-b0]=sound base
                                 (signed 8 bit Pulse Coded Modulation samples)
                   
                Ŀ
                 Sound Counter [b23-b0]=sound counter
                                        if=sound end then
                                                     event report on Timer A
                                                     interrupt XOR GPIPb7
                
                    Ŀ
                     Sound End [b23-b0]=sound end
                    
                     Ŀ
                      LMC MASK  b15-b0=microwire interface mask for LMC1992
                                       (shifted to left during transmission)
                                       0:masked
                                       1:transmitted
                     
                     Ŀ
                      LMC DATA  b15-b0=microwire interface data
                               [b1-b0]=10 for National Semiconductor LMC1992
                               [b2-b0]=address        [b5-b0]=data
                                       000:input              000001:DAC+GI
                                                              000010:DAC
                               
                                       001:bass               000000:-12 dB
                                                              ......
                                                              000110:  0 dB
                                                              ......
                                                              001100:+12 dB
                               
                                       010:treble             000000:-12 dB
                                                              ......
                                                              000110:  0 dB
                                                              ......
                                                              001100:+12 dB
                               
                                       011:volume             000000:-80 dB
                                                              ......
                                                              010100:-40 dB
                                                              ......
                                                              101000:  0 dB
                               
                                       100:right fader        000000:-40 dB
                                                              ......
                                                              001010:-20 dB
                                                              ......
                                                              010100:  0 dB
                               
                                       101:left  fader        000000:-40 dB
                                                              ......
                                                              001010:-20 dB
                                                              ......
                                                              010100:  0 dB
                     
